This invention relates to a power take-off shaft and master shield arrangement of the type finding special utility in the agricultural tractor field, wherein the power take-off shaft is used for driving associated implements. It is common to refer to such a power take-off shaft as a PTO shaft, and such designation shall be used throughout the specification and claims.
In agricultural and general purpose tractors a PTO shaft extends rearwardly of the tractor to receive a drive shaft associated with a trailing implement. Safety shields are provided as regular equipment with the sale of tractors and implements to protect the operator from the exposed portion of the tractor PTO shaft and the front universal joint of the implement drive shaft. It has been found, however, that the operator is frequently not concerned with his own safety but rather is concerned with the speed of assembling and disassembling the tractor trailing implements from the tractor. As a result, the safety shields are frequently removed and not replaced. It has heretofore been recognized that it is desirable to provide a safety shield that will not necessitate its entire removal during assembly and disassembly operations and which will automatically resume its safety covering position even though the operator negligently leaves it in a raised position.
The foregoing general results have heretofore been obtained in such patented structures as those disclosed in U.S. Pat. No. 2,443,035 to Hardy, U.S. Pat. No. 2,858,680 to Harrington, U.S. Pat. No. 2,967,432 to Shane et al., U.S. Pat. No. 3,389,763 to Meinert, and U.S. Pat. No. Re 30,152 to Davis. However, these constructions leave much to be desired in the way of accommodating the positioning of the shield and in simplicity of construction and operation.